Tetramethyltetrahydronaphthalene purification process

Abstract

An improved process for the removal of by-product amounts of undesirable aromatic hydrocarbon compounds from a mixture comprised of such compounds and predominantly tetramethyltetrahydronaphthalene is provided. In accordance with the process the mixture is contacted with a concentrated sulfuric acid solution whereby the undesirable aromatic hydrocarbons are dissolved therein and the acid phase containing said hydrocarbons is removed from the mixture.

What is claimed is: 
     
       1. A process for the removal of by-product amounts of aromatic hydrocarbon compounds from a mixture comprised of aid compounds and predominantly tetramethyltetrahydronaphthalene comprising the steps of: contacting said mixture with a sulfuric acid solution containing in the range of from about 90% to about 100% by weight sulfuric acid in an amount sufficient to cause the dissolution of said aromatic hydrocarbon compounds; and   separating the resulting acid phase containing said aromatic hydrocarbon compounds from said mixture.   
     
     
       2. The process of claim 1 wherein said mixture comprised of said undesirable aromatic hydrocarbon compounds and tetramethyltetrahydronaphthalene is produced by reacting dichlorodimethylhexane with benzene in the presence of aluminum chloride catalyst. 
     
     
       3. The process of claim 2 wherein said aromatic hydrocarbon compounds are comprised of dihydronaphthalenes and indenes. 
     
     
       4. The process of claim 2 wherein said amount of said sulfuric acid acid solution contacted with said mixture is in an amount in the range of from about 2% to about 20% by volume of said mixture. 
     
     
       5. The process of claim 2 wherein said sulfuric acid solution contains about 96% by weight sulfuric acid and said mixture is contacted therewith in an amount in the range of from about 5% to about 10% by volume of said mixture. 
     
     
       6. In a process of preparing tetramethyltetrahydronaphthalene wherein dichlorodimethylhexane is reacted with benzene in the presence of aluminum chloride, the improvement wherein byproduct amounts of aromatic hydrocarbons are removed from the reaction mixture produced comprising the steps of: combining said reaction mixture with a sulfuric acid solution containing in the range of from about 90% to about 100% by weight sulfuric acid in an amount of from about 2% to about 20% by volume of said reaction mixture so that said aromatic hydrocarbons are caused to be dissolved in said sulfuric acid solution; and   separating the resulting acid phase containing said undesirable aromatic hydrocarbons from said reaction mixture.   
     
     
       7. The process of claim 6 wherein said aromatic by-products are comprised of dihydronaphthalenes and indenes. 
     
     
       8. The process of claim 7 wherein said concentrated sulfuric acid solution contains about 96% by weight sulfuric acid. 
     
     
       9. The process of claim 8 wherein said sulfuric acid solution is combined with said reaction mixture in an amount in the range of from about 5% to about 10% by volume of said mixture. 
     
     
       10. The process of claim 9 wherein said reaction mixture is distilled prior to combining said sulfuric acid solution therewith and said sulfuric acid solution is combined with the distillate obtained. 
     
     
       11. The process of claim 10 wherein said process is carried out at a temperature in the range from about room temperature to about 45° C. 
     
     
       12. The process of claim 5 wherein said process is carried out at a temperature in the range of from about room temperature to about 45° C.